Javan Rhino

The Javan rhino is probably the rarest large mammal on the planet, with only 57 left in the wild and none in captivity. And every single Javan rhino lives within the confines of the Ujung Kulon National Park in Indonesia, making the species even more vulnerable to extinction.

However, the population has been inching up over the past five years and the creation of a second population could soon provide the species with some much-needed extra breathing - and breeding - space.

Javan rhino in Ujung Kulon National Park in Indonesia. There are only 57 left on earth, making it the rarest of the world's 5 rhino species

Physical description

The Javan rhino is dusky grey. It can reach up 4m in length and 1.7m in height, and weigh as much as 2.3 tonnes. It is very similar in appearance to the closely related greater one-horned rhino, although it is slightly smaller, has a much smaller head, and looser, less apparent skin folds.

The species has a single horn of about about 25 cm. The upper lip is pointed and can be used to grasp food and bring it to the mouth.

Life cycle

There are still major gaps in our knowledge about Javan rhinos because they are extremely difficult to study. The remaining Javan rhinos live in incredibly dense jungle and the species has never bred in captivity.

For these reasons, the average lifespan is unknown, but it is probably between 30-40 years. It is also assumed - based on the biology of the greater one-horned rhino - that females become sexually mature at 5-6 years and males at 10 years.

The mating season occurs roughly from July to November, but the gestation period is also unknown, athough it is probably around 16 months - similar to the greater one-horned rhino.

The Javan rhino is solitary, except when pairs form for mating and when mothers tend their young.

Diet

In the tropical rainforest where the species now survives, it is a pure browser, but it was possibly a mixed feeder (both browse and grass) in other parts of its historic range.

Population and distribution

The Javan rhino historically roamed across a vast swathe of Asia from north-eastern India through Myanmar, Thailand, Cambodia, Laos, Vietnam, and the Indonesian islands of Sumatra and Java.

But over the past 150 years, its range and population has shrunk dramatically. And now there is just one population in a single national park in the Ujung Kulon peninsula on the Indonesian island of Java. The population has been inching upwards over recent years and has now reached 57.

The authorities are now considering creating a second population to ease the pressure on Ujung Kulon national park and give the species a greater chance of long term survival.

The last Javan rhino outside Ujung Kulon died in 2010 in Cat Tien National Park in Vietnam. It had been shot and its horn removed. The species was officially declared extinct in Vietnam the following year.

What are the main threats?

Since there is only one surviving population, the species is extremely vulnerable to extinction, especially as they face a number of serious threats.

Javan rhinos were killed across their range by trophy hunters during colonial times. More recently, they have been poached - like other rhino species - for their horns. Poaching ultimately wiped out the species in Vietnam and remains an ever-present threat to the last rhinos in Java.

Another concern is habitat loss and degradation. While the remaining Javan rhinos live within a national park, surrounding forests are under pressure from human activities. And even with the Udung Kulon National Park, the rhinos find themselves threatened by the invasive Arenga palm, which is having a devastating impact on the plants that the rhinos rely on for food.

The small size of the Javan rhino population is also a cause for concern. Low genetic diversity could make it hard for the species to survive diseases or natural disasters, like volcanoes or earthquakes.

A photo of a dead, young Javan Rhino in Indonesia. Poaching remains a threat to the species, which is probably the rarest large mammal on earth.

We have brought white, black and Indian rhinos back from the brink of extinction. Now it's time to do the same for the Javan rhino.

Dr Barney Long, WWF-US

What is WWF doing?

As early as 1962, WWF pioneered scientific research on these rare animals. And we are continuing to conduct important studies today, helping to reveal critical information on the rhino's behavioural patterns, distribution, population size, sex ratio and genetic diversity.

We also support anti-poaching patrols in Indonesia's Ujung Kulon National Park, along with efforts to enhance their existing habitat by reducing human encroachment and competition for food with banteng (endangered wild cattle), and by conducting studies to increase the availability of the rhino's natural food supply by halting and reversing the invasion of Arenga palm.

WWF is also working with the government and partners to study the feasibility of translocating rhinos from Ujung Kulon National Park to establish a second population in another suitable and secure habitat.

How you can help

Don't buy rhino horn products. The illegal trade in rhino horn continues to pose one of the greatest threats to rhinos today.

Use and support sustainable wood, paper and palm oil. By purchasing certified sustainable palm oil and FSC-certified forest products, retailers, traders, and manufacturers can help protect Javan rhino habitat. Consumers can also play their part by demanding certified products.